Form movement is a collective term for mechanical watch movements, which are not circular and adapt the shape of the watch case, for exaple rectangular, barrel-shaped or arcade-like.
Today form movements are rather a rarity because of the extinct of mechanical movements during the so-called quartz crisis. But now they are increasingly developed again by some manufacturers, because high manufacture competence counts as an undisputed advantage in the market. Among the best known manufacturers of form movements are Jaeger-LeCoultre and Patek Philippe.